Polymer blends containing propylene polymers and ethylene copolymers are known. For example, U.S. Pat. No. 3,433,573, issued Mar. 18, 1969 to Holladay et al., discloses compositions containing blends of 5 to 95% by weight of a propylene polymer containing a major amount of propylene and 95 to 5% by weight of a copolymer of ethylene with a polar monomer such as vinyl acetate, methyl methacrylate, vinylidene carbonate, alkyl acrylates, vinyl halides and vinylidene halides. However, the only ethylene copolymer used in the examples is an ethylene-vinyl acetate copolymer. These compositions are said to be useful in fibers, films and molded articles of improved dyeability and low temperature characteristics.
U.S. Pat. No. 3,555,110, issued to McConnell et al. on Jan. 12, 1971, discloses that ethylene copolymers such as ethylene/alkyl acrylate, ethylene/aryl acrylate and ethylene/alkenyl carboxylate copolymers are compatible with alpha-monoolefin block polymers such as propylene/ethylene polymers having from about 50% to 99% by weight of polypropylene segment in the polymer chain. Objects prepared from these polymer blends are said to have excellent clarity, improved low temperature properties and good impact strength at low temperature.
U.S. Pat. No. 4,774,277, issued on Sep. 27, 1988 to Janac et al., discloses compositions useful in the preparation of film which is said to be soft and have high tensile, tear and impact strength. The compositions contain polyolefin plastics blended with an elastomeric plasticizer. The disclosed polyolefin plastics are polypropylene, polypropylene reactor copolymer, polybutylene, linear low density polyethylene, high density polyethylene or mixtures thereof. The elastomeric plasticizer contains (1) polyethylnne or a copolymer of ethylene and an unsaturated ester of a lower carboxylic acid, (2) olefin elastomer, such as copolymers of ethylene with higher alpha-olefins such as propylene containing about 30-90 weight percent ethylene, and (3) a hydrocarbon oil.
U.S. Pat. No. 4,835,218, issued May 30, 1989 to Yoshimura et al., discloses a composition for shrinkable film which is said to have good heat sealability, transparency, strength, and low temperature quick shrinking properties. The composition contains specific combinations of (A), (B) and (C), i.e., the combinations of (A)+(B), (B)+(C), and (A)+(B)+(C), wherein (A) is non-rigid polyolefin resins such as ethylene-vinyl acetate, (B) is an elastomer comprising a specific ethylene-alpha-olefin copolymer and an elastomer consisting of block copolymer having at least one monovinyl substituted aromatic hydrocarbon polymer block and at least one polyolefin polymer block selected from at least one saturated polymer or unsaturated polymer made from mainly aliphatic conjugate diene derivative, and (C) is rigid polyolefin resins such as polypropylene.